Fix discovery of commits behind a version when version.json is in a subdir of repo

Fixes #342

Author: AArnott

src/NerdBank.GitVersioning/GitExtensions.cs

@@ -281,7 +281,7 @@ public static IEnumerable<Commit> GetCommitsFromVersion(this Repository repo, Ve
 
             var possibleCommits = from commit in GetCommitsReachableFromRefs(repo)
                                   where version.Revision == -1 || commit.Id.StartsWith(objectIdLeadingValue, objectIdMask)
-                                  let buildNumberOffset = VersionFile.GetVersion(commit)?.BuildNumberOffsetOrDefault ?? 0
+                                  let buildNumberOffset = VersionFile.GetVersion(commit, repoRelativeProjectDirectory)?.BuildNumberOffsetOrDefault ?? 0
                                   let versionHeight = commit.GetHeight(c => CommitMatchesMajorMinorVersion(c, version, repoRelativeProjectDirectory))
                                   where versionHeight == version.Build - buildNumberOffset
                                   select commit;